Hmm, interesting. Now at this point I would use
HexCmp to quickly check all the differences between the original and your edit. When I figured out where the color triplets were placed I used it to highlight all the differences between two
very similar EFP files for talisman glows (red and blue, the only thing that changed the file size was just a few texture references). You can get a fifteen day trial if you want. The best way to figure stuff out is by experimenting.
Anyway, you got the green so you got the triplets right. If you used HexCmp you could first check the Diffuse sections of the EFP file to see if you did anything more to them than change the triplets and if that's what caused the oddity. Otherwise you must have changed another section of the file by accident. Keep us updated with what you figure out.